1. Field of the Invention
The present invention relates to an image forming apparatus, an image forming system and an image forming control method, and specifically relates to a technology for appropriately handling a retention paper sheet when retention paper sheets, remaining within the apparatus or the system, have generated at the time when a certain abnormality has occurred.
2. Description of Related Art
When an abnormality, such as a paper jam, etc., has occurred at a certain position within an image forming apparatus, such as a copier, a printer, a facsimile apparatus, a printing machine, etc., operations of the image forming apparatus concerned is deactivated by controlling actions performed by a control section. Further, after deactivating the operations of the image forming apparatus concerned, the control section conducts controlling operations for implementing the purge processing. The purge processing is defined as such a technology for collecting plural retention paper sheets, currently remaining within the image forming apparatus, onto an ejecting tray disposed at a single position so as to collectively eject them.
Further, in a case where an image forming operation using a massive amount of paper sheets is implemented, the image forming operation is resumed from the page at which the concerned abnormality had occurred, after the abnormal paper sheet has been removed. On that occasion, successive to the final page outputted just before the occurrence of the abnormality, the page same as that at which the abnormality had occurred is to be outputted. Accordingly, it becomes possible not only to continuously implement the image forming operation as if the abnormality did not occurred, but also to prevent the paper sheets from being wasted.
In this connection, with respect to an operation for processing a abnormality, such as the paper jam as above-mentioned, etc., each of Japanese Patent Application Laid-Open Publication 2012-150523, Japanese Patent Application Laid-Open Publication 2011-145558, Japanese Patent Application Laid-Open Publication 2010-152087 and Japanese Patent Application Laid-Open Publication 2005-335861 sets forth various kinds of the related technologies.
In this connection, in order to resume the operation for forming images onto successive paper sheets after removing the abnormal paper sheets, it is necessary to discriminate the abnormal paper sheets, which are to be ejected from the image forming apparatus, and the subsequent normal paper sheets from each other, so as not to mingle them with each other. In other words, it is necessary to control the image forming apparatus to make the subsequent normal paper sheets, outputted after the occurrence of the abnormality, continue to the normal paper sheets, outputted before the occurrence of the abnormality concerned, so as not to yield a dropout paper sheet or duplicated paper sheets.
Japanese Patent Application Laid-Open Publication 2012-150523 above-cited sets forth such a devisal that the paper sheet is reversed after the occurrence/resolution of the abnormality, and outputted. However, according to this technology, only such a user who has grasped this function may be able to discriminate them from each other.
Further, according to the technology set forth in Japanese Patent Application Laid-Open Publication 2012-150523 above-cited, if the image forming operation is resumed without removing the abnormal paper sheets, it becomes difficult to discriminate the normal paper sheets and the abnormal paper sheets from each other. In addition, in a case of the single-side image forming operation, it is possible to recognize existence or non-existence of the reversed paper sheets, but in a case of the duplex image forming operation, it may become extremely difficult to determine whether or not the paper sheet concerned is reversed.
Still further, Japanese Patent Application Laid-Open Publication 2011-14558 above-cited proposes that, when the operation for manually removing the abnormal (or jammed) paper sheet is faster than the automatic removing operation therefor, the automatic removing operation, employing the purge processing, is disabled. However, the above-cited patent document fails to propose that the abnormal paper sheets and the subsequent paper sheets are discriminated from each other in the automatic removing operation so as not to mingle them with each other.
Still further, Japanese Patent Application Laid-Open Publication 2010-152087 above-cited proposes that the image-formed paper sheets, on which images are already formed, are ejected in such a manner that none of the page dropout exist even if a certain abnormality occurs. However, the above-cited patent document fails to propose that the abnormal paper sheets and the subsequent paper sheets are discriminated from each other in the automatic removing operation so as not to mingle them with each other.
Still further, Japanese Patent Application Laid-Open Publication 2005-335861 above-cited proposes that the retention paper sheets remaining at the time of jam occurrence is to be ejected onto the sub-tray. However, since Japanese Patent Application Laid-Open Publication 2005-335861 premises that a plurality of ejecting trays is provided in the apparatus, it is impossible to cope with above-mentioned feature in a case where only a single tray is provided in the apparatus concerned.
Yet further, even according to any one of the other conventional technologies concerned, all of the eject-able paper sheets are either to be ejected or to be retained. In other words, there has been such a problem that it is impossible to sufficiently cope with the operation for preventing the paper sheet from being duplicated, or the operation for preventing a retention paper sheet from remaining at a removing difficult position.